Taylor Schilden was originally inspired to study the interactions among climate, tectonics, and landscape evolution by the stunning river canyons of southwest Peru, which she was fortunate to visit several times during her PhD research. Since 2015, she has been a professor with a joint appointment at the GFZ Potsdam and the University of Potsdam in Germany. Her research now focuses on how climate and tectonic forcing influence landscape form, erosion rates, erosion processes, and sedimentation patterns. This work commonly includes numerical modeling and empirical data derived from thermochronology and/or cosmogenic nuclides. Her field-based studies have spanned the Central and Patagonian Andes, Central Anatolia, the Himalaya, and the East African Rift. She is the first female Editor-in-Chief of the AGU journal Tectonics since the journal’s inception in 1982.

CONFERENCIA MAGISTRAL

HIDROGEOLOGÍA DE TÚNELES

Areas with strong orographic rainfall gradients, including the eastern side of the Central Andes, have been commonly shown to have strong spatial gradients in erosion rates. Drainage-divide migration, controlled by rock-uplift and differential erosion rates, may play an important role in the geomorphic evolution of mountain ranges, but they remain empirically poorly constrained.

Geomorphological evidence suggests that the Sierra de Aconquija, on the eastern side of the southern Central Andes in northwest Argentina, is currently undergoing westward drainage-divide migration. The range has been subjected to near-vertical rock uplift and pronounced orographic rainfall for the last several million years, presenting an ideal test case for using low-temperature thermochronometric data to explore its topographic evolution. We perform three-dimensional thermal-kinematic modeling of previously published thermochronometric data spanning the windward and leeward sides of the range to explore its likely structural and topographic evolution. We find that the data can be explained by scenarios involving pure topographic evolution through drainage-divide migration, or by scenarios that involve changes in the structures that have accommodated deformation through time. By combining new 10Be derived catchment-average denudation rates with geomorphic constraints on probable fault activity, we conclude that the evolution of the range was likely dominated by west-vergent faulting on a high-angle reverse fault that underlies the range, together with drainage-divide migration at a rate of several kilometers per million years.

Our findings place new constraints on the magnitudes and rates of drainage-divide migration in real landscapes, quantify the effects of orographic rainfall and erosion on the topographic evolution of a mountain range, and highlight the importance of considering drainage-divide migration when interpreting thermochronometer age patterns in areas where orographic rainfall drives spatial gradients in erosion rates.